API – Application Programming Interface, a set of routines and parameters with descriptions to manage by some software objects, components or programs or hardware devices

Aspect Ratio – this term usually means a proportion of a picture width to its height, and describes how a picture to be displayed. For instance DVD Video standard uses either 4:3 or 16:9 aspect ratios

ASF – Advanced Streaming Format also known as Advanced Systems Format is Microsoft media container for multiplexed video, audio, pictures and metadata streams, intended for storing media as files or broadcasting trough Microsoft Windows Media Servers. At this page - ASF specification can be found

ASF Mutual Exclusion – a possibility provided by ASF specification to enable / disable a certain stream inside ASF file to simultaneous playback. For example if a file comprises a few audio tracks with different languages and mutual exclusions, Windows Media Player will be able to play only one audio per time but deliver an option to select other languages. Some technical – Mutual Exclusions

Demultiplexing – a process of splitting input file or stream to separate elementary logical data streams, like video, audio, subtitles, closed captions etc, for further processing like decoding, rendering and so forth

DirectShow – Microsoft software architecture intended for media playback, transcoding, streaming, capture, editing and other applications. The main idea is to isolate a certain operations with data to separate objects, called DirectShow filters and define their interaction. It is a subset of DirectX SDK to be a part of Windows SDK (formerly Platform SDK). The latest available separate version is DirectX 9.0 SDK Update (February 2005) Extras

GOP – group of pictures, in term of video compression, a group of encoded video frames that starts with K-Frame and contains some delta frames which, depending on video compression type (MPEG-2, AVC, VC1 etc.), can reference to previous or subsequent video frames to be properly decoded. GOP length depends on video codec settings and usually varies from 0.5 second (in MPEG-2) to 10 or more seconds (in MPEG-4)

K-Frame – key frame, is a type of video frames that in terms of video temporal compression does not require another video data to be decoded, as it does not refer to previous or subsequent going frames. For example, within MPEG-2 video, key frames are named Intra-frames (I frames), but within Motion JPEG (MJPEG) or Digital Video (DV) all video frames are encoded as key frames

FOURCC – four bytes character code (consisted of ASCII symbols), that usually identifies video encoded or raw type, e.g. YUY2, dv50 or MP42. Technical info can be found at MSDN - FOURCC Codes article. Enumeration of many existing and reserved FOURCC codes with descriptions - Video Codecs and Pixels Formats

Motion Estimation – an algorithm to be used in video encoding techniques with temporal compression to find similar picture objects among subsequent frames. It is uses to “predict” part of one frame from another and encode not full picture but only changes that happen from frame to frame

PAL – Phase Alternating Line, the set of analog TV standards such as PAL-B, PAL-D, PAL-N etc. Among a lot of technical characteristic most of PAL’s standards define a frame resolution to be 625 lines ( with 576 active or visible lines) / 50 fields per second

SDK – software developer kit intended for programmers to build SDK’s components or libraries to own applications. SDK usually consists of some DLLs, Libraries or executable binaries, samples demonstrating their usage and reference manuals

Windows Media Player – Microsoft software for playback a wide range of media files and Windows Media being broadcasted. Up to the version 6.4 it was completely DirectShow based. Starting with 7.0 and further for playback Windows Media files (ASF, WMV, WMA, etc.) it uses DMO technology. That is a link to an official page - media player